Beam Instrumentation Performance and Plans · 2017-06-26 · Beam Instrumentation Performance and Plans Alexander Aleksandrov Beam Instrumentation Team Leader January 11, ... for

Beam Instrumentation

Performance and Plans

Alexander Aleksandrov

Beam Instrumentation Team Leader

January 11, 2012

2 Managed by UT-Battellefor the U.S. Department of Energy Presentation_name

RING44 Position

54+ Loss

1 Current

12 Fast Loss

5 Electron Detectors

2 Electron Profile Scanner

2 Transverse BTF

SCL34 Position and Phase

33+ Loss

9 Laser Wire

24 Neutron Detectors

HEBT29 Position and Phase

26+ Loss,

3 Fast Loss

10 Wires

4 Current

2 Bunch Shape

6 Scrapers Charge

1 Laser emittance

IDump3 Position

1 Wire

6 Loss

2 Current

2 Video

EDump1 Current

4 Loss

1 Wire

LDump6 Loss

6 Position

2 Wire

CCL10 Position and Phase

9 Wires

48 Loss

1 Faraday Cup

4 Bunch Shape


MEBT6 Position and Phase

2 Current

5 Wires

1 CHUMPS

1 Emittance

DTL10 Position and Phase

5 Wire

4 Loss

5 Faraday Cup

6 Current


SNS Beam Instrumentation Systems

are Numerous, Diverse and Growing in Number

RTBT17 Position

26 Loss

5 Wires

4 Current

1 Harp

3 Fast Loss

1 Target Imaging

MDump4 Loss

2 Current

1 Wire

BCM, BLM,

BPM, BSM,

WS….15+ systems


Outline

• Status and upgrade plans for selected systems:

– Nominal Operation

• Beam Loss Monitors

– Machine Tuning

• Beam Position and Phase Monitors

– Beam Power Increase

• Foil Image and Temperature

• Ring Transverse Feedback and Beam Transfer Function Measurement

– Machine Study and Loss Reduction

• Transverse Profiles and Halo

• Transverse Emittance

• Longitudinal Profiles


Beam Loss Monitors (BLMs)

• Major tool for machine protection and tune up

• Ionization Chamber Detectors (307)

• Scintillation Detectors (55)

– Neutron detectors

– Fast loss detectors

• Multi-channel analog front-end VME cards

• Digital electronics in VME crate

• VxWorks software

• Very reliable

• Hardware obsolescence is looming problem

• Short term solution: stock up on spares

• Long term solution: new system


New BLM development

• Guiding Principles:

– Compatible with existing EPICS and MPS infrastructure

– Less custom, more off-the-shelf components

– No major functionality changes

• Analog Front End:

– Single channel Individual cards

– Provision for analog background subtraction

– Chassis satisfies “technical transparency”

– Have had two chassis installed in SCL for testing

• Digital Processing:

– Have not decided yet on what to use

– National Instruments Compact RIO chassis is under consideration

– New Compact RIO FPGA processor for HEBT scrapers is being installed

• requirements are similar to BLM

Courtesy of A. Zhukov

New analog front-end card

NI CRIO chassis


Beam Position and Phase Monitors (BPMs)

• Main tool for machine tune-up and troubleshooting

– Phase measurements for linac tune-up

– Position measurements for trajectory correction, injection set-up and centering beam on dumps and target

• 160 strip-line pick-ups

– 96 “linac type” operate at 402.5MHz and 805MHz

– 64 “ring type” operate at low frequency

• Custom made PCI analog front-end and digital cards

• LabView software under embedded Windows XP on individual PCs (one per pick-up), 6Hz trigger rate

• Meets all accuracy specs but reliability is not stellar

• Hardware obsolescence is major problem

– Parts, cards, PC motherboards, OS upgrades

• Short term solution: stock up on spares

• Long term solution: new system

PCI board

BPM PC

BPM pick up


New BPM development

• Guiding Principles:

– Compatible with existing EPICS and Reference RF infrastructure

– Less custom, more off-the-shelf components

– No major functionality changes but 60Hz capable

• Analog Front End:

– As similar to SNS LLRF front-end card as possible

– Investigating need for continuous TDR self-calibration

– Chassis satisfies “technical transparency”

– Plan to have 1 chassis for testing by end of FY12

• Digital Processing:

– Have not decided yet on

– needs more processing power than BLM

– National Instruments Flex RIO in PXIe chassis is under consideration

– Plan to have 1 chassis for testing by end of FY12

Goal: deploy 1 new ‘linac type’ BPM in FY12 summer shutdown

for in-the-field performance evaluation

History of BPM TDR self-calibration data


Injection Foil Imaging System

• Analog in-tunnel radiation hard camera has been used for injection foil imaging

– Expensive maintenance

– Not suitable for time-resolved optical pyrometry

– Not optimal for foil shaking observation due to fixed and limited update rate (30Hz)

• New optical transmission line with digital camera outside of tunnel

– High-End scientific cameras can be used

– Infrared detectors can be used for temperature measurements

– No maintenance in radiation areas


Optical transmission line

• Two 8” flat mirrors mounted on the wall in the tunnel

• A commercial off-the-shelf 6” telescope

• Digital scientific camera and/or other detectors


Photo diode

Bandpass

Filter

Adapter

Foil Temperature Measurements

Two-color optical pyrometer

Photo diodeFilters

Black body radiationFoil

Courtesy of W. Blokland


Ring Transverse Feedback System

• Suppressing e-p instability is primary goal

– 1-300MHz bandwidth

– 200/400 W/channel peak power

• Have analog LLRF system commissioned

• Digital LLRF is being commissioned

Comb

filter

Low Level RF

TTL

Beam

Kicker + Cable

RF Power

Amplification

Fiber optic

delay

Pickup + Cable

Courtesy of C. Deibele

BPM and kicker tuning

Feedback electronics

Measured system bandwidth


Ring Transverse Feedback /

BTF Measurement System Performance

• Have demonstrated e-p instability suppression, but results are not repeatable and consistent

• Have implemented Beam Transfer Function (BTF) measuring technique

• Have observed unexpected, and so far unexplained beam response

– Can be a key to successful e-p damping

• Digital LLRF promises more flexibility in system tuning

Courtesy of R. Hardin

Low intensity beam BTF High intensity beam BTF

Effect of feedback on e-p instability


Beam Study Diagnostics

• Improve performance through machine knowledge

– Understand initial 6-d beam distribution

– Understand beam dynamics in real machine

– Tune / validate beam model

– Optimize beam transport

• Demands to diagnostics

– Complex beam pulse structure requires fine time resolution

– Small beam loss requires large dynamic range

– As many measured projections as possible: transverse profiles, longitudinal profiles, 2-d projections

• Direct measurement of 6-d distribution is not practical

– As many measurement locations as possible

• We can not meet all demands in one diagnostic – use variety of complimentary measurements


Transverse 1-D Profile Measurements

• Wire scanners in warm linac and transport lines (41)

– Interceptive: max pulse width = 50us

– 10us time resolution

– Dynamic range = 10,000

• Laser Wire in super-conducting linac (9+1)

– Non-interceptive

– 10ns time resolution

– Dynamic range = 100

• Electron beam scanner in accumulator ring (1)




Wire scanner

Laser Wire

station

Ring electron

beam scanner


Status and Plans

• Wire scanners status

– Updated computers (PCs)

– Upgraded LabView to 2009

– Developed new software

• Wire scanners plans

– Increase scan speed

– Investigate and mitigate dynamic range limitations

High resolution beam profiles in HEBT• Electron profile scanner status

– Expert run system

– Limited scan aperture

– Limited measured beam maximum intensity due to limited electron gun voltage

• Electron profile scanners plans

– Improve electron beam optics

– Develop user friendly software

– Increase maximum electron gun voltage

– Increase scan aperture Time-resolved transverse beam profile in Ring


Transverse 2-D Emittance Measurements

• Slit – harp emittance station in MEBT


– 10us time resolution


• Laser emittance station in HEBT




• Tomographic reconstruction using wire scanners


– 10 us time resolution

– Dynamic range = ?

MEBT emittance scanner principle of operation

HEBT laser emittance scanner principle of operation


Emittance Measurements Status and Plans

• MEBT emittance status

– Updated computer (PC)


– Developed new software

• MEBT emittance plans

– Increase dynamic range to ~ 10,000

– Reduce integration time to < 1us

• HEBT laser emittance status

– Recently commissioned

– Details in next presentation

• HEBT laser emittance plans

– Finalize EPICS GUI

– Unify data analysis software with MEBT

– Investigate and mitigate dynamic range limitations

MEBT horizontal MEBT vertical

HEBT verticalHEBT horizontal


MEANT Tomographic Reconstruction of 2-D

Emittance from 1-D Profiles Courtesy of T. Gorlov

• Reconstruction seems to works very well in HEBT

– Need to verify using laser emittance measurements

– High resolution of wire scan data help with algorithm convergence

• Plan to extend to SCL, Warm Linac, MEBT

– Requires good transport model

– Problem of space charge

Reconstructed 2-d distribution

Comparison of measured and reconstructed profiles


Longitudinal 1-D Bunch Profile Measurements

• Beam Shape Monitors (aka Feschenko monitor ) in CCL and HEBT (4+3)


– ~1° @805 MHz ( 3.5 ps) intra-bunch resolution

– 10us averaging time


• Mode-lock-laser monitor in MEBT (1)


– ~ 3° @402.5 MHz (20ps) intra-bunch resolution

– 10us averaging time


– Non-operational currently

– Status and plans in next talk

CCL BSM

I(φ) Analyzed beam

Utar

g

1 32 4 5

6

7Signal

I(z)Secondary

electrons

B

Z X Y

X

BSM principle of operation


BSM Status and Plans

Measured longitudinal bunch size vs. model

Distance [m]

rms

ph

as

e w

idth

[d

eg]

1º .5º

Typical longitudinal bunch profile

no beam

phase [deg]

am

plitu

de

[a.u

.]

• Beam Shape Monitor status

– Upgraded computer hardware (PC)


– New software

– Upgraded BSM hardware on 2 CCL BSMs to improve resolution to ~.5°

• Beam Shape Monitor plans

– Upgrade remaining BSMs hardware

– Study and mitigate resolution limitations

– Collaborate with INR (Feschenko) on laser BSM development


New BSM EPICS GUI

Courtesy of R. Dickson• Fully independent parallel scans

• Extensive set of troubleshooting and tuning tools


A near-term wish list

• MEBT vertical scrapers

– Not funded in FY12

• Ring Ionization Profile Monitor (IPM)

– Design 90% complete


• Ring electron scanner aperture increase


• Laser stripping experiment set-up


• Laser based BSM


• New Ring pinger electrode


• RFQ test stand diagnostics



Summary

• Existing Beam Instrumentation is capable to support machine tuning and production runs

• Downtime associated with beam diagnostics is low

• Moving steadily toward increasing dynamic range of measurements and implementing more non-perturbing diagnostics to support beam study

• Working on improving GUIs and speeding up data collection

• Approaching state-of-the-art for many systems– working closely together with AP team to ensure trustworthiness

of data

Documents

Beam Instrumentation Performance and Plans · 2017-06-26 · Beam Instrumentation Performance and Plans Alexander Aleksandrov Beam Instrumentation Team Leader January 11, ... for